General Instrument SP0256

GI SP0256 refers to a family of closely related NMOS LSI chips manufactured by General Instrument in the early 1980s, able to model the human vocal tract by a software programmable digital filter, creating a digital output converted into an analog signal through an external low-pass filter.

The SP0256 (and its predecessor, the SP0250) implements a 12-pole, Linear Predictive Coding (aka LPC-12) all-pole Vocal Tract Model (VTM).

This is in contrast to its contemporaries, such as Texas Instruments LPC Speech Chips, which used an 8 kHz sample rate with a 10-pole model, and realized their VTM with a lattice filter.

The chip was also sold under the Archer brand by RadioShack stores as the "Narrator Speech Processor" (part number 276-1784), where earlier documentation incorrectly identified it as the SPO256 (with the letter "O" instead of the numeral "0").

Used in a prototype Fuzzbuster radar detector,[citation needed] the SP0264-021 has relevant phrases and is pin compatible to the SP0256 series.

An FPGA implementation of a classic eighties speech synthesizer SP0256, done for the Retro Challenge in October 2017 by Niels Moseley, is available on his GitHub account.